This invention relates to a vertical wall structure that is pre-engineered and prefabricated so that it can be constructed on the site where a sound barrier or a visual screen is desired. The wall structure is made of prefabricated wood which gives off a warm, natural appearance. Unlike concrete or masonry walls, there is no "prison wall" feeling associated with the present out-of-doors wall structure. Applicant's wall structure is neighborly because it is identical in appearance and attractiveness from either side with no unsightly backside. In spite of its lighter weight, the present wall structure functions to reduce noise as well as solid concrete or masonry competing structures.
Applicant's wall structure is constructed entirely of a pressure treated wood which is easy to install, economical and aesthetically pleasing. It's ready to install when delivered and requires no concrete footings, heavy equipment or special skills for installation.
The wall structure of this invention consists almost entirely of posts and panels of prefabricated pressure treated wood which can be erected at the site so as to enjoy the advantages of the "sandwich" construction. By virtue of this construction, the panels can be made so that they are relatively thick, for example, 21/2" to 3" thick and they are secured to the posts in channels created by pressure treated 4".times.4" "cants" (4.times.4's ripped diagonally prior to treatment) that are spiked to the posts. The panels consist of plywood faces and pressure treated lumber in between the faces. The tough plywood faces provide a stiff structural skin to enable the panels to resist high wind loads. The posts are embedded in the ground to a depth of at least one half of the exposed height of the wall structure and backfilled with crushed stone.
The effectiveness of any noise barrier is determined by many factors. Two of the most important are noise, leaks (openings), and mass (weight). In applicant's wall structure, the panels are free of noise leaks because of their two-sided covering of dimensionally stable pressure treated wood. In addition to being free of noise leaks, Applicant's wall structure has sufficient mass to produce the same field noise reduction as much heavier and expensive concrete and masonry barriers. The minimum panel mass to assure good acoustic performance is 4 lbs./sq.ft. Applicant's panels weight considerably more, 5.5 lbs/sq.ft, which assures good acoustical performance.